Our bodies need vitamins and essential minerals, but if taken in large amounts they can adversely affect our health. Large amounts of many vitamins and minerals can be toxic.

Nutritional Status

Individuals can have deficient, adequate, or toxic intakes of any essential nutrient. A deficiency occurs when the intake is too low to meet a person’s need for that specific nutrient. Adequacy occurs when a person gets enough, but not too much, of a nutrient. Nutrient toxicity occurs when a person gets an overdose of a given nutrient.

Dietary Reference Intakes

The National Academy of Sciences, Institute of Medicine, established Dietary Reference Intakes (DRIs), which can be used when planning and assessing the diets of the healthy general population, as well as for other purposes. The DRIs are a set of nutrient-based reference values: the Estimated Average Requirement (EAR), the Recommended Dietary Allowance (RDA), the Adequate Intake (AI), and the Tolerable Upper Intake Level (UL). These terms are defined in Table I.

Table I. Dietary Reference Intakes

Estimated Average Requirement (EAR): the average daily nutrient intake level estimated to meet the requirement of half the healthy individuals in a particular life stage and gender group.

Recommended Dietary Allowance (RDA): The average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals in a particular life stage and gender group.

Adequate Intake (AI): The recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate. Used when an RDA cannot be determined.

Tolerable Upper Intake Level (UL): The highest average daily intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.

An essential nutrient has either an EAR and RDA, or an AI for a specific gender/life stage group (such as female/ 19-30 years), depending upon whether sufficient data are available to set an EAR. If the data are insufficient, an AI is given for that group.

Because many individuals eat fortified foods (foods containing nutrients added during processing) and dietary supplements, ULs have been set for many essential nutrients for a specific gender/life stage group. The UL is the highest level of daily nutrient intake considered safe for almost all individuals in a specific group.

These ULs are based on intakes from food (including fortified food), water, and dietary supplements, unless otherwise stated. The UL is for daily use over a long period of time. ULs are not available for all essential nutrients for each gender/life stage grouping because data regarding adverse effects frequently are limited.

Nutrient Toxicity

The UL is calculated from hazard identification (primarily evidence of adverse effects) and dose-response data. The appropriate critical adverse effect(s) for the nutrient is considered in setting the no-observed-adverse-effect level (NOAEL). This is the highest intake or dose of a nutrient at which no adverse effects have been observed in individuals studied. If no adequate data are available to determine the NOAEL, then a lowest-observed-adverse-effect level (LOAEL) is used. This is the lowest intake or dose at which an adverse effect(s) has been demonstrated.

The ULs of vitamins and essential minerals for adults are given in Table II. ULs have been established for boron (20 mg), nickel (1 mg), and vanadium (1.8 mg); however, EARs or AIs have not been set for these minerals. The reasons given by the Institute of Medicine, National Academy of Sciences for the UL and the basis for the UL are listed in Table II.

Reasons given by the Institute of Medicine,
National Academy of Sciences for UL

Basis for UL
(NOAEL or
LOAELb/per day)

RDA or AIc
(per day)
Men/Women

Daily Valued
(per day)

Vitamin A (preformed)

3,000 mcg

The critical adverse effect is liver abnormalities except for women of childbearing age in which it is teratogenicity. Other adverse effects include nausea, vomiting, headache, increased cerebrospinal fluid pressure, vertigo, blurred vision, muscular incoordination, bulging, fontanel in infants, nervous system changes, and bone and skin abnormalities.

No adverse effects from consumption of vitamin E naturally occurring in foods. The critical adverse effect of high intakes from fortified foods, dietary supplements, or pharmacologic agents is increased tendency to hemorrhage. Adults deficient in vitamin K, including those taking coumarin drugs, have increased risk of coagulation defects.

LOAEL = 500 mg/kg

15/15 mg α-tocopherol

30 IU (22 mg of natural
d-α-tocopherol acetateh)

Vitamin K

NDi

No adverse effects from consumption from foods or dietary supplements.

No adverse effects from consumption from foods or dietary supplements. There have been occasional reports of anaphylaxis to parenteral thiamin as well as pruritus due to allergic sensitivity to thiamin injection.

NE

1.2/1.1 mg

1.5 mg

Riboflavin
(vitamin B2)

ND

No adverse effects from consumption from foods or dietary supplements.

NE

1.3/1.1 mg

1.7 mg

Niacing (nicotinic acid and nicotinamide)

35 mg

No adverse effects from consumption of naturally occurring niacin in foods. The UL for nicotinic acid is based on vasodilation (flushing). Nicotinamide appears not to be associated with the flushing effects. There are gastrointestinal effects for patients treated with nicotinic acid. Hepatic toxicity has been reported in patients treated medically with the vitamin.

LOAEL = 50 mg

16/14 mg

20 mg

Vitamin B6

100 mg

No adverse effects from consumption from food sources. The critical adverse effect from high intake is neuropathy.

NOAEL = 200 mg

1.3, 1.5, or 1.7 mgk

2.0 mg

Folateg

1,000 mcg

No adverse effects have been associated with the consumption of folate levels in foods or fortified foods. Excess folate may precipitate or exacerbate neuropathy in vitamin B12-deficient individuals.

LOAEL = 5 mg

400/400 mcgl

400 mcg

Vitamin B12

ND

No adverse effects from consumption from foods or dietary supplements.

NE

2.4/2.4 mcgm

6.0 mcg

Pantothenic Acid

ND

No adverse effects have been associated with high intakes.

NE

5/5 mg

10 mg

Biotin

ND

No adverse effects from foods or dietary supplements.

NE

30/30 mcg

300 mcg

Choline

3.5 g

The critical effect is hypotension; fishy body odor is a secondary consideration. Also nausea and diarrhea.

LOAEL = 7.5 g

550/425 mg

NE

Calcium

2.5 g

The critical effect is kidney stone formation or milk-alkali syndrome (hypercalcemia and renal insufficiency). Also affects absorption of iron, zinc, magnesium, and phosphorus.

LOAEL = 5000 mg

1,000 or 1,200 mgn

1,000 mg

Phosphorus

3 or 4 go

The critical effect is hyperphosphatemia. Other effects include hypocalcemia, adjustments in calcium-regulating hormones, and calcification of nonskeletal tissues (especially kidneys).

NOAEL = 10,200 mg

700/700 mg

1,000 mg

Magnesium

350 mg

Adverse effects are from nonfood sources, such as magnesium salts used for pharmacologic purposes. The critical effect is osmotic diarrhea. Other effects include nausea, abdominal cramping, serious neurological and cardiac symptoms, and death.

LOAEL = 360 mg

310, 320, 400, or 420 mgp

400 mg

Fluoride

10 mg

The critical effect is skeletal fluorosis.

NOAEL = 10 mg

4/3 mg

NE

Selenium

400 mcg

The critical effects are hair and nail brittleness and loss. Other effects include gastrointestinal disturbances, skin rash, garlic breath odor, fatigue, irritability, and nervous system disorders.

NOAEL = 800 mcg

55/55 mcg

70 mcg

Iron

45 mg

The critical adverse effect is gastrointestinal side effects. Other effects include impaired zinc absorption, increased risk for vascular disease and cancer, and systemic iron overload.

No adverse effects have been convincingly associated with excess intake of chromium from food or dietary supplements.

NE

20, 25, 30, or 35 mcgr

120 mcg

Molybdenum

2 mg

The UL is based upon impaired reproduction and fetal development in rats and mice. Molybdenum compounds appear to have low toxicity in humans, but inadequate data are available.

NOAEL = 0.9 mg/kg (from rat data)

45/45 mcg

75 mcg

Potassium

ND

No adverse effects from consumption from foods. Individuals with impaired urinary potassium secretion may have adverse effects.

NE

4,700/4,700 mg

3,500 mg

Sodium

2.3 g

The adverse effects of blood pressure is the scientific rationale. Some people are salt-sensitive. Other adverse effects include cardiovascular abnormalities, increased urinary calcium excretion, osteoporosis, gastric cancer, and asthma.

LOAEL = 2.3 g

1,200, 1,300 or 1,500 mgs

2,400 mg

Chloride

3.6 g

Because chloride is assumed to be in foods in equimolar quantities, the UL for chloride was set based on that of sodium.

NE

1,800, 2,000 or 2,300 mgt

2,400 mg

aUL = The maximum level of daily nutrient intake that is likely to pose no risk of adverse effects.bNOAEL = No-observed-adverse-effect level; LOAEL = Lowest-observed-adverse-effect level.cRDA = Recommended Dietary Allowance; AI = Adequate Intake.dThe Daily Value is used in nutritional labeling of food products and dietary supplements. The values given are for individuals age 4 years and above.e5 mcg vitamin D for 19-50 year olds, 10 mcg for 51-70 year olds, and 15 mcg for those above 70 years.fAs a-tocopherol; applies to any form of supplemental a-tocopherol.gThe ULs for vitamin E, niacin, and folate apply to synthetic forms from supplements, fortified foods, or a combination of supplements and fortified foods.hThe conversion of IUs to mg a-tocopherol depends on the form.iND = Not determinable due to lack of data of adverse effects.jNE = Not established.k1.3 mg vitamin B6 for 19-50 year olds, 1.5 mg for women age 51 and above, and 1.7 mg for men age 51 and above.lAll women capable of becoming pregnant should consume 400 mcg from supplements or fortified foods in addition to intake of food folate from a varied diet.mAdults over 50 years are advised to meet their RDA mainly by consuming foods fortified with vitamin B12 or a supplement containing vitamin B12.n1,000 mg calcium for 19-50 year olds and 1,200 mg for those 51 years and older.o4 g phosphorus for adults 19-70 years old and 3 g for those above 70 years.p310 mg magnesium for women 19-30 years, 320 mg for women 31 years and above, 400 mg for men 19-30 years, and 420 mg for men 31 years and above.q8 mg iron for men and for women 51 years and older and 18 mg for women 19-50 years.r20 mcg chromium for women 51 years old and above, 25 mcg for women 19-50 years old, 30 mcg for men 51 years old and above, and 35 mcg for men 19-50 years old.s1,200 mg sodium for individuals over 70 years old, 1,300 mg for those 51-70 years old, and 1,500 mg for those 19-50 years old; moderate physical activity.t1,800 mg chloride for those over 70 years old, 2,000 mg for those 51-70 years old, and 2,300 mg for those 19-50 years old.

The current RDAs or AIs, as well as the Daily Values for these essential nutrients, are also given in Table II. Daily Values are set by the Food and Drug Administration for use in nutritional labeling on food products and dietary supplements. RDAs or AIs are not the same as Daily Values. Information from older releases of the RDAs were used in setting the Daily Values. The RDAs or AIs and Daily Values for these essential nutrients are included in Table II so that you can compare these values to the ULs. These values are also useful in planning and evaluating diets, as diets should meet the RDAs or AIs for an essential nutrient without exceeding the ULs.

Diets for healthy individuals should not routinely exceed the UL for any essential nutrient; however, intakes above the UL may be appropriate for investigation within clinical research trials. Nutrient ULs are not meant to apply to individuals who may be given an essential nutrient under medical supervision.